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90psi compression on cold motor
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Posted by: Banshee_370

just did my 1st compression check on my 250r. came out to 90 psi cold. i can press down the kicker with my hand, not easy but still able to get it down there.

motor is stock only a pipe and filter. it will still start up and run no problems. we figured to top end is going but could it be something else? no coolant leaking anywhere

thanks

Posted by: machwon

It could be a bad head gasket or warped head, but that will pressurize the radiator and make it lose coolant. Compression testers can really vary in readings and normally 90 psi won't start. Usually something that low you have to pull start.

Do yourself a favor and rebuild the topend immediately. A piston/bore with that low of compression would have a piston well beyond its recommended use. The skirts are probably cracked and your riding a motor bomb. If the piston breaks, now your looking at potential crank damage, cylinder damage, crankcase damage, and so it can get more expensive if you wait.

Posted by: Honda 250r 001

be sure to open the throttle all the way when your kicking over with the gauge on.

Posted by: Banshee_370

throttle was wide open

Posted by: Honda 250r 001

quote:
Originally posted by Banshee_370
throttle was wide open

defeneatly way way way over due for a rebuild.

Posted by: 86 Quad R

i would say that its about time to freshen her up.

Posted by: Banshee_370

little update, i went out and bought a new craftsman compression gauge with a whole bunch of adapters.

hooked up mu 14mm long (same thread size/length as spark plug) held the throttle wide open and kicked it 6-8 times. gauge reads 180psi even. dont know maybe if we used the wrong adapter last time? or didnt screw it in enough, or maybe gauge is broke.

readings were on a cold motor

Posted by: 86 Quad R

thats about where it needs to be for running pump gas. amazing what a new gage will do for ya ehhh?

Posted by: Honda 250r 001

quote:
Originally posted by 86 Quad R
thats about where it needs to be for running pump gas. amazing what a new gage will do for ya ehhh?

your suppose to kick it over until the needle stops going up, i would try kicking over more than 6-8 times, and see what it reads... just to be 100 percent sure.

Posted by: deathman53

I checked my motor with the same gauge(that read wrong), it showed 120 psi, later it got up to 150, its still 60-70 psi off from what it should be. Honestly, if I put that gauge on my motor thinking it was 100%, I would think the motor was toast too. Thats what I thought at first, later on I thought about if the guage is off or wrong. I'm gonna buy a new gauge also. I got 2 new gauges, I read 210 with one and the one that steve bought w/ long reach, I got 215. I just for a joke tried my old tester, it turned out to be the check valve inside the nozzle that was a problem, thats why it read wrong. Now my right foot hurts from kicking this motor over many times.

Posted by: Banshee_370

the gauge stopped climbing at about 8 kicks

i kicked 220 on my banshee, now im starting to think that its "too new" lol

Posted by: Honda 250r 001

quote:
Originally posted by Banshee_370
the gauge stopped climbing at about 8 kicks

i kicked 220 on my banshee, now im starting to think that its "too new" lol

220 on a banshee??? DANG you running strait race fuel in that thing?

Posted by: Banshee_370

c12